In the field of medicine, imaging and image guidance are a significant component of clinical care. From diagnosis and monitoring of disease, to planning of the surgical approach, to guidance during procedures and follow-up after the procedure is complete, imaging and image guidance provides effective and multifaceted treatment approaches, for a variety of procedures, including surgery and radiation therapy. Targeted stem cell delivery, adaptive chemotherapy regimes, and radiation therapy are only a few examples of procedures utilizing imaging guidance in the medical field.
Advanced imaging modalities such as Magnetic Resonance Imaging (MRI) have led to improved rates and accuracy of detection, diagnosis and staging in several fields of medicine including neurology, where imaging of diseases such as brain cancer, stroke, Intra-Cerebral Hemorrhage (ICH), and neurodegenerative diseases, such as Parkinson's and Alzheimer's, are performed. As an imaging modality, MRI enables three-dimensional visualization of tissue with high contrast in soft tissue without the use of ionizing radiation. This modality is often used in conjunction with other modalities such as Ultrasound (US), Positron Emission Tomography (PET) and Computed X-ray Tomography (CT), by examining the same tissue using the different physical principals available with each modality. CT is often used to visualize bony structures, and blood vessels when used in conjunction with an intra-venous agent such as an iodinated contrast agent. MRI may also be performed using a similar contrast agent, such as an intra-venous gadolinium based contrast agent which has pharmaco-kinetic properties that enable visualization of tumors, and break-down of the blood brain barrier. These multi-modality solutions can provide varying degrees of contrast between different tissue types, tissue function, and disease states. Imaging modalities can be used in isolation, or in combination to better differentiate and diagnose disease.
In neurosurgery, for example, brain tumors are typically excised through an open craniotomy approach guided by imaging. The data collected in these solutions typically consists of CT scans with an associated contrast agent, such as iodinated contrast agent, as well as MRI scans with an associated contrast agent, such as gadolinium contrast agent. Also, optical imaging is often used in the form of a microscope to differentiate the boundaries of the tumor from healthy tissue, known as the peripheral zone. Tracking of instruments relative to the patient and the associated imaging data is also often achieved by way of external hardware systems such as mechanical arms, or radiofrequency or optical tracking devices. As a set, these devices are commonly referred to as surgical navigation systems.
Another such example of image guided surgery includes fluorescence imaging wherein fluorescing agents are used to detect tumors and potentially other cancerous pathologies and their margins. This method can detect microscopic tumors or residual lesions that may be easily missed during surgery due to size, color, or the lack of other visual or haptically differentiable cues, and/or other factors inhibiting detectability, which may hinder the identification of a tumor or lesion and the differentiation of healthy tissue from pathological tissue.
Since image-guided surgical procedures are complex in nature and the risk associated with use of such procedures is very high, the surgical staff must often resort to performing a simulated rehearsal of the entire procedure. Unfortunately, the tools and models that are currently available for such simulated rehearsal and training exercises typically fail to provide a sufficiently accurate simulation of the procedure.